Lua协程学习

按照书上码了下，但运行有问题，暂时不知道原因：

function send (x)
	coroutine.yield(x)
end
 
function producer()
  return coroutine.create( function ()
	 while true do
	  local x = 1
	  send(x)
	  end
	end)
end
 
function receive(prod)
	local status, value = coroutine.resume(prod)
	return value
end
 
function filter (prod)
	return coroutine.create(function()
		a = {1,2,3,4,5,6,7,8,9,10}
		for line , k in pairs(a) do
		local x = receive(prod)
		x = string.format("%5d %s",line,x)
		send(x)
		end
	end)
end
 
function consumer (prod)
	while true do
		local x = receive(prod)
		print(x)
	end
end
 
consumer(filter(producer()))

　　之后再来细看，主要是 producter-consumer模型。